Decking device for mine cages and the like conveyances

ABSTRACT

A decking device for use in a hoisting system of the general type having a shaft and a conveyance supported in the shaft by a cable. The device has two jaws movable in a guide towards each other to a first position in which they engage a structure on the conveyance to immobilize the same in the shaft, and away from each other through a second position in which one of the jaws is in contact with the structure to a third position in which the jaws are retracted and can no longer contact the structure. The jaws are driven between the first and third positions at a controlled speed to eliminate any tendency for the conveyance to move uncontrollably in the shaft due to stretch in the cable.

United States Patent m a V Apr. 2, 1974 I DECKING DEVICE FOR MINE CAGES AND THE LIKE CONVEYANCES Primary Examiner-Richard Acgerter [75] Inventor: lvan Falkland Watt, Florida Park, Assistant kmmmeriiamcs Rowlunfi.

. South Africa Attorney, Agent, or I:rmYoung and lhomson [73] Assignee: Anglo American Corp. of South some: fringed, Johannesburg, 57] ABSTRACT [22] Fil d; S t 5 [972 A decking device for use in a hoisting system of the general type having a shaft and a conveyance sup- [2! 1 Appl. No.. 286,260 ported in the shaft by a cable. The device has two jaws movable in a guide towards each other to a first posi- [30] Foreig A li ti P i i D tion in which they engage a structure on the convey- Sept- 9 [97 South Africa M052 ance to immobilize the same in the shaft, and away Oct 1971 South Africa 71/7166 from each other through a second position in which one of the jaws is in contact with the structure to a [52] Cl 187/73 third position in which the jaws are retracted and can {51] Int. Cl 5/16 no longer Contact the Structure The j are driven [58] Field of Search 8O 81 between the first and third positions at a controlled 187/82 speed to eliminate any tendency for the conveyance to move uncontrollably in the shaft due to stretch in the [56] References Cited cable UNITED STATES PATENTS 8 Claims 4 Drawing Figures 922,375 5/1909 Wright 187/73- DECKING DEVICE FOR MINE CAGES AND THE LIKE CONVEYANCES This invention relates broadly to hoisting systems of the type consisting of a shaft and a conveyance which may be raised or lowered in the shaft by means of a cable. More particularly the invention relates to a decking device for use in such systems. In the context of this specification the term decking device means a device for controlling the positioning of the conveyance at a specific point in the shaft.

It is a well-known fact that the cable supporting a mine cage in a shaft can stretch quite considerably. In one South African mine, for example, a stretch of 7 feet has been detected at a level of 7,600 feet. This gives rise to all kinds of problems.

The present invention is concerned with the problem created by cable stretch during loading or unloading of a mine cage at a deep level. 'Let us assume that a fullyloaded cage reaches a specific station at a deep level in a shaft. As the cage is unloaded at this station it will get progressively lighter and it will consequently rise in the shaft under the influence of the cable stretch. This obviously hampers further unloading. On the other hand, as an empty cage is loaded at a deep level, it will get progressively heavier and it will therefore descend in the shaft under the influence of the stretch. Once again,

this will tend to hamper further loading.

This problem can of course be partially resolved by simply immobilizing the cage at the specific station during loading or unloading and this has in fact already been suggested. This is by no means a final solution however. Consider for example the case where an empty cage has been immobilized at the required level and the cage has thereafter been fully loaded. As soon as the cage is released from the immobilizing means it will drop for a short distance because of the increased stretch in the cable. This will cause bouncing which in turn might cause the cable to snap. Conversely, when an emptied cage is released from the immobilizing means, the cage will tend to rise in the shaft because of the decreased cable stretch.

It is an object of the present invention to provide a decking device for eliminating the above-mentioned problem.

A decking device according to the invention comprises two jaws guided for movement towards each other to a first position in which they define a gap between them and are adjacent a fixed plane, and away from each other through a second position in which the gap is lengthened but the jaws are still adjacent the fixed plane, to a third position in which the jaws are retracted behind the fixed plane, means to move the jaws from the third position to the first position, and means tomove the jaws from the first position to the third position at a controlled speed.

Further according to the invention the jaws are located and guided for movement on an elongated track.

Further according to the invention a camelback is formed in the track adjacent each end thereof to enable the jaws to be moved into their third positions.

Further according to the invention chain sprockets are located at each end of the track, and there are provided chains extending around the sprockets and connected to the jaws, and means to drive at least one of the sprockets in either direction.

A hoisting system according to the invention comprises a shaft, a conveyance adapted to be raised or lowered in the shaft by means of a cable, at least one pair ofjaws mounted on a side of the shaft and guided for movement towards each other to a first position in which they are able to engage with fixed structure on the conveyance to immobilize the conveyance in the shaft and in which the jaws are adjacent a fixed plane, and away from each other through a second position in which the jaws are still adjacent the fixed plane, to a third position in which the jaws are retracted behind the fixed plane, means to move the jaws from the third position to the first position, and means to move the jaws from the first position to the third position at a carefully-controlled speed so that any tendency for the conveyance to rise or fall uncontrollably in the shaft due to stretch in the cable is eliminated in that the conveyance is forced to follow at least one of the jaws until the second position is reached.

Furtheraccording to the invention the jaws are located and guided for movement on an elongated track.

Further according to the invention a camelback is formed in the track adjacent each end thereof to enable the jaws to be moved into their third positions.

Further according to the invention chain sprockets are located at each end of the track, and there are provided chains extending around the sprockets and connected to the jaws, and means to drive at least one of the sprockets in either direction.

To illustrate the invention an embodiment thereof is described hereunder with reference to the accompanying drawing in which:

FIG. 1 shows a cross-section of a mine shaft, a mine cage and the decking device of the invention;

FIG. 2 shows a side view of one half of the decking device with the clamps in their locking positions;

FIG. 3' is similar to FIG. 2 except that the clamps are shown in their retracted positions; and FIG. 4 shows the arrangement of the chain sprockets, chains and clamps.

With reference to FIG. 1 a mine cage 10 is supported from a rope 11 in a shaft 12. In the drawing the cage is at a specific station 13 at which it can be loaded or unloaded with men or materials.

The decking device of the invention consists essentially of two tracks14 which are mounted on either side of the shaft 12 and which extend a predetermined distance (depending on the maximum rope stretch which is likely to be encountered) above and below the sta-' tion 13.

Although there are two tracks per device only one track is illustrated in FIGS. 2 and 3. With reference to these drawings the track 14 consists of a central straight portion 15 and a camelback 16 at each end thereof. The term camelback" is intended to mean that the portions 16 of the track have been cranked out of the plane occupied by the straight portion 15. Two carriages are slidably attached to the track. One carriage carries a lower clamp 17 and the other carriage carries an upper clamp 18.

The carriages are adapted to be driven by a hydraulic motor 19 by means of chains 20 and 21 as illustrated in FIG. 4. With reference to this drawing one end of the chain 20 is attached to the upper carriage. The other end passes around a sprocket 22 on the motor 19 and w is attached to the lower carriage. One end of the chain 21 is attached to the lower carriage. The other end passes around the idler sprocket 23 and is attached to is rotated in a clockwise direction (with reference to FIG. 4), the two carriages will move away from each other. In other words, from the positions shown in FIG. 4, the upper carriage will move upwards along the track and the lower carriage will move downwards along the track. Conversely, if the motor is now driven in an anticlockwise direction, the carriages will move towards each other until they abut each other at about the midpoint of the track;

A projection 24 is provided on the cage on each of the sides facing a track. In use, the carriages on each track are initially in their respective camelbacks 16 as illustrated in FIG. 3. In these positions the clamps l7 and 18 on each track are withdrawn from the line of travel of the projections 24 on the cage so that the cage can move freely in the shaft without being fouled by the clamps.

Let us assume now that the case 10 is fully loaded and that it has reached the station 13 where it is to be unloaded. The rope '11 will have stretched in accordance with the load carried by the cage.

On reaching the station 13, the motor 19'is rotated in an anti-clockwise direction. The causes the carriage on each tract to move out of their camelbacks l6 and approach each other until they abut the lower and upper sides of each of the projections 24 as shown in FIG. 2. The cage will therefore be securely immobilized in the shaft and unloading can take place without the cage moving away from the station under the effect of therrope stretch. When the cage has been emptied there will be a tendency for the cage to rise in the shaft as explained in the beginning of this specification but this will be prevented by the clamps.

The motor 19 is then rotated in a clockwise direction at a carefully controlled slow speed. This causes the carriage and their clamps on each track to move away from each other at the same controlled speed.

The cage will of course now be free to move upwards. However the upper side of each of the projections 24 will still be abutting the upper clamps in each track and, accordingly, the cage will only be able to move upwards in the shaft at the same speed as that of the clamps. In other words the cage will move upwards under the influence of the rope stretch at a controlled speed and any uncontrolled movement of the cage due to rope stretch is eliminated. Ultimately the cage will reach a new position in the shaft which is determined by its decreased load. The carriages will however continue tomove apart until they are all once again in their respective camelbacks at which time hoisting can commence to bring the cage to the surface or to another station as the case may be.

Similarly, where the cage is initially empty and has been fully loaded at'the station 13, the separation of the clamps will cause the cage to drop as a result of the increased ropestretch. The projections 24 will however still rest on the lower clamps in each track and the cage will thereforefall in the shaft in a controlled manner only until the new position of equilibrium has been reached at which time hoisting of the cage can safely commence.

I claim:

l. A hoisting system comprising a shaft, 21 conveyance adapted to be raised or lowered in the shaft by means of a cable, at least one pair ofjaws mounted on a side of the shaft and guided for movement towards each other to a first position in which they are able to engage with fixed structure on the conveyance to immobilize the conveyance in the shaft and in which the jaws are adjacent a fixed plane, and away from each other through a second position in which the jaws are still adjacent the fixed plane, to a third position in which the jaws are retracted behind the fixed plane in a direction away from the conveyance, means to move the jaws from the third position to the first position, and means to move the jaws from the first position to third position at a controlled speed so that any tendency for the conveyance to rise or fall uncontrollably in the shaft due to stretch in the cable is eliminated in that the conveyance is forced to follow at least one of the jaws until the second position is reached.

2. A hoisting system as claimed in claim 1 in which the jaws are located and guided for movement on an elongated track. 7 1

3. A hoisting system as claimed in claim 2 in which a camelback is formed in the track adjacent each end thereof to enable the jaws to be moved into their third positions.

4. A hoisting system as claimed in claim 2 including chain sprockets located at each end of the track, chains extending around the sprockets and connected to the jaws, and means to drive at leastone of the sprockets in'either direction.

5. A hoisting system as claimed in claim 1 in which a pair of jaws is located on each of two opposed sides of the shaft, and formations are provided on the sides of the conveyance facing the said sides of the shaft, the formations being adapted to be clamped between the jaws in the first position.

6. A hoisting system as claimed in claim 2 in which the elongated track is vertical.

7. A hoisting system as claimed in claim 1 in which said first and second positions are spaced apart from each other vertically.

8. A hoisting system as claimed in claim 1 in which said fixed plane is vertical. 

1. A hoisting system comprising a shaft, a conveyance adapted to be raised or lowered in the shaft by means of a cable, at least one pair of jaws mounted on a side of the shaft and guided for movement towards each other to a first position in which they are able to engage with fixed structure on the conveyance to immobilize the conveyance in the shaft and in which the jaws are adjacent a fixed plane, and away from each other through a second position in which the jaws are still adjacent the fixed plane, to a third position in which the jaws are retracted behind the fixed plane in a direction away from the conveyance, means to move the jaws from the third position to the first position, and means to move the jaws from the first position to third position at a controlled speed so that any tenDency for the conveyance to rise or fall uncontrollably in the shaft due to stretch in the cable is eliminated in that the conveyance is forced to follow at least one of the jaws until the second position is reached.
 2. A hoisting system as claimed in claim 1 in which the jaws are located and guided for movement on an elongated track.
 3. A hoisting system as claimed in claim 2 in which a camelback is formed in the track adjacent each end thereof to enable the jaws to be moved into their third positions.
 4. A hoisting system as claimed in claim 2 including chain sprockets located at each end of the track, chains extending around the sprockets and connected to the jaws, and means to drive at least one of the sprockets in either direction.
 5. A hoisting system as claimed in claim 1 in which a pair of jaws is located on each of two opposed sides of the shaft, and formations are provided on the sides of the conveyance facing the said sides of the shaft, the formations being adapted to be clamped between the jaws in the first position.
 6. A hoisting system as claimed in claim 2 in which the elongated track is vertical.
 7. A hoisting system as claimed in claim 1 in which said first and second positions are spaced apart from each other vertically.
 8. A hoisting system as claimed in claim 1 in which said fixed plane is vertical. 